Circuit interrupter



Nov. 20, 1945. c. 1 DENAULT 2,389,346

CIRCUIT INTERRUPTER Filed Aug. 8, 1942 l @d/Tw ATTOR Patented Nov. 20, 1945 CIRCUIT INTEREUPTER Clinton L. D'enault, Sharon, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application August 8, 1942, Serial No. 454,135

16 Claims.

This invention relates to circuit interrupters, and more particularly to circuit interrupters of the type which create arcing pressure in a substantially closed arcing chamber.

In circuit interrupters of the type which draw an arc in an arc extinguishing medium, such as oil, to facilitate the interruption of the arc, it is desirable to get rid of the contaminated arc eX- tinguishing medium which results during a circuit interrupting operation. When oil is used, carbonized products of decomposition tend to remain in the arcing chamber and to lower the dielectric strength of the oil remaining therein. Where opening and reclosing operations are frequent this contamination of the are extinguishing medium Within the arcing chamber is especially undesirable.

It is, therefore, an object of the present invention to provide an improved ushing system for flushing the decomposed are extinguishing medium out of the arcing chamber following a circuit opening operation. A

It is more specifically an object of the present invention to utilize the arcing pressure to energize such a flushing system and to render the same operative following the subsidence of arcing pressure within the arcing chamber.

Another object of the present invention is to provide an improved circuit interrupter which increases the arc length by making one of the relatively movable contacts responsive to the pressure within the arcing chamber. Consequently, the arc length will be increased not only by the normal operation of the movable contact mechanism, but also by additional movement of the stationary contact in response to the arcing pressure. During the interruption of high currents, the arcing pressure will correspondingly increase and the arc will be lengthened at an increased rate as compared to the lengthening of the arc during interruption of low currents.

It is a specific object of the present invention to provide a circuit interrupter in which the stationary contact is movable in response to arcing pressure and is operative in a ushing container to result in a ilushing of the arcing chamber following a circuit opening operation.

Another object of the present invention is to provide a circuit interrupter having an arcing chamber which communicates through suitable valve means to an adjacently disposed iiushing chamber in which is placed resilient means responsive to the pressure created in the arcing chamber to render said flushing chamber operative. In such a flushing chamber a piston may be disposed, or a volume multiplying piston may be positioned.

My invention is not limited to use only in liquid type circuit interrupters, for it will be apparent to one fully understanding its principles that it is applicable to circuit interrupters which generate arcing pressure in other mediums such as gases or even air.

By way of illustration and not by way of limitation, I describe my invention as used in liquid type circuit interrupters.

Further objects and advantages will become readily apparent upon a reading of the following specification considered in conjunction with the accompanying drawing, in which:

Figure 1 is a view in cross section of a liquid type circuit interrupter embodying the present invention and shown in the closed circuit position;

Fig. 2 is a fragmentary view in cross section of a further embodiment of the present invention;

Fig. 3 is a fragmentary view in section of a further embodiment of the present invention;

Fig. 4 is a fragmentary view in cross section of another liquid type circuit interrupter embodying the present invention;

Fig. 5 is a fragmentary view in section showing another embodiment of the present invention; and

Fig. 6 is a fragmentary View in section of another form which the present invention may assume.

Referring to the drawing, and particularly to Fig. l, the reference numeral I designates the cover of a tank of conventional design, through which the movable contact 2 reciprocates being guided by an insulating bushing 3. The tank is lled with a suitable arc extinguishing liquid 4, such as oil. Immersed in the oil is a metallic arc interrupting chamber 5 provided with an insulating liner 5a into which the movable contact 2 extends, being guided therein by the insulating bushing 6.

Disposed at the lower end of the arc interrupting chamber 5 is a stationary contact 'l electrically connected to a line terminal 8, only a part of which isshoWn. It Will, therefore, be apparent that the electrical circuit through the interrupter comprises the movable contact 2, stationary contact 1 rand line terminal 8. A bleeder opening 9 is provided tov permit the gradual seepage of remaining gas bubbles out of the arc interrupting chamber 5 following a circuit opening operation.

When the circuit interrupter is opened the movable contact 2 is drawn upward away from the stationary contact 'I to assume a position indicated by the dotted lines Ill, in which position there is provided an annular space between the reduced portion of the movable contact 2 and the insulating guide bushing 6 which is indicated by the reference numeral I I. It is, consequently, apparent that in the open circuit position, indicated by the dotted lines IIJ, decomposed gas and liquid particles may flow out of the arc interrupting chamber through the annular space I I. A second bleeder opening 9a. may also be provided to assist the bleeder opening 9 in permitting gas bubbles to escape after an interrupting operation. v v

When the movable contact 2 is drawn upward away from the stationary contact I an arc will be drawn which will react upon the oil Within the arc interrupting chamber 5 to create high arcng pressure. It is desired to utilize this arcing pressure to energize the flushing system which is operated following the subsidence of pressure within the arc interrupting chamber 5. For this purpose I have provided an adjacently disposed metallic chamber I2 which cornmuhicates by valves I;3 and I4 with the arc interrupting chamber 5. At the upper end of chamber I2 is a space I5 lled with a compressible uid such as air.

When the movable contact 2 separates from the stationary contact 'I to draw an arc, the pressure created by theestablishment of said arc will act through the valve I3 to place the compressible fluid in the region I5 under pressure, the valve I4 remaining closed during this time. When the movable contact A2 is raised to the position indicated by the dotted lines I0, the arc pressure within the chamber 5 will decrease dueto the venting through therannular space II.` At this time the valve I4 will open to permit the compressed iluid in the region I5 to force oil within the chamber I2 to pass through the valve I4 in the direction of the arrows I6. Since the distance from the valve I3 Ato the valve I4 is considerable, fresh oil of high dielectric strength will pass through the valve I4 to flush out the arc interrupting chamber 5 carrying the deionized products of decomposition upward through the annular space II. Bleeder openings II and I8 are provided in the chamber I2 to permit oil to flow into the ushing chamber I2 following a flushing operation. However, the bleeder openings I'I and I8 are not of suiicient size to interfere with the flushing operation.

It will be "observed that rfor a portion of the upward travel ofthe movable contact 2 the insulating guide bushing 6 is substantially closed thus permitting the pressure within the arc inter-4 rupting chamber 5 to have sufficient time to act through the valve I 3 to compress the compressible fluid I5. Further upward travel 'of the movable contact 2 opens the annular passage II to permit a reduction of pressure within the arc 'interrupting chamber 5 and a consequent operation of the flushing system.

y In rthe "embodiment of my invention shown in Fig. 2 the Varrangement is similar to that previously described in connection with Fig. 1. However, a piston I9 is provided within the ushing chamber I2, being biased upwards 'bya compression spring 29 against a flange 2| 'integrally formed with the flushing chamberv I2. The operation of the liiushi'ng system shown in Fig. 2 is similarto that previouslydscribed in connection withFig. l. Howeventhe provision of thevpiston i9fslidably operative in the Aiiushin'g chamber I2 adds at least two desirable features. The piston I9 prevents contamination of the ilushing oil contained in the flushing chamber I2 below the piston I9, indicated by the reference numeral 22, by the contaminated discharge products passing from the arc interrupting chamber 5 through the valve I3 above the piston I9. Consequently, only fresh oil of high dielectric strength passes in the direction indicated by theV arrows I6 through the Valve I4 following a subsidence of the arcing pressure within the arc interrupting chamber 5. The presence of the piston I9 also permits the use of a large bleeder opening indicated by the reference numeral 23, since this bleeder opening 23 can be substantially sealed when the piston I9 is in its initial position. The provision of the compression spring 20 permits a rapid restoration of the piston I9 to its normal position.

In the circuit interrupter shown in Fig. 3 a volume multiplying piston 24 is providedV to produce an increased flow of fresh oil of high dielectric strength through the valve I4 in the direction of the arrows I5. Consequently, a small volume of highly compressed gas I5 will produce a large volume movement of flushing oil. During the downward motion of the Volume multiplying piston 24, oil is drawn through the aperture 25, which may be of considerable size, to the back side 26 of the enlarged portion 21 of the Volume multiplying piston 24. A rapid unimpeded downward movement of the volume multiplying piston 24 is thus achieved. Dur-ing the retraction of the volume multiplying piston 24 vby the compression spri-ng 29, the valve -28 opens to permit oil to pass from the back side 26 of the enlarged portion 2'I through the valve 28 into the region 22 for the next operation.

In the circuit interrupter shown in Fig. 4 a piston 29 is provided whichl slidably operates through a wall of the arc interrupting chamber 5. The other end of the piston 29 is operative in a ushing chamber A resilient washer member 3| made of flexible material, 4such as leather,v is attached by a screw 32 to the lower end of the piston 29. A compression spring 33 biases the piston 29 into the chamber 5. The diameter of the ushing chamber 39 is made relatively large t0 contain a considerable quant-ity of oil. A valve 34 is provided at the end of the piston 29 eX- tending within the arc interrupting chamber v5, the purpose for which will lappear more 4clearly hereinafter. A iiuid connection 35 through the piston 29 is provided which communicates at its upper end with the valve 34 and at its lower end with an aperture A36 which opens to the region above the washer member 3 I.

The operation of the hushing system illustrated in Fig. l will new lbe explained. When the movable contact 2 Vis, Imoved upward Yaway from the stationary contact TI, an arc will be drawn to create pressure within the arc interrupting chamber 5. This pressure will -act upon the piston .29, maintaining the valve A34 closed, to cause downward motionof the piston 2-9 in to the ushing chamber 36. The resilient washer member 3i will flex to permit a passage of cil to the top side thereof, the spring V33 mean-while being compressed. When the pressure within the arc interrupting chamber5 decreases suiiciently following the interruption of the arc, the compression spring 63 will retract the piston v29 `toi-its upward position, forcing oilabove the washer member y3l through the aperture 36 and through thewfluid connection 35 toppen the val-ve 34 and flush'the lower end of the chamber 5. The size of the ilushing chamber 30 is sufficient so that the quantity of oil used for fiushing purposes is suicient to cover Ythe stationary contact 1. The flushing of the lower portion of the arc interrupting chamber will wash the products of decomposition upwards within the chamber 5 out through the annular venting passage I I (not shown in Fig. 4, see Fig. 1)

The circuit interruptor shown in Fig. 5 ccmprises a stationary contact 31 which is slidably movable through a guide web 38, in this instance formed as an integral part of the metallic arc interrupting chamber 5. A washer member 39 serves as a check valve to close the apertures 40 through the guide Web 38. The lower end of the stationary contact 31 is threadedly secured to a piston 4I slidably operative in a piston casing 42. The piston 4I is biased upwardsl by a compression spring 43. A washer member 44 slidable on the stationary contact 31 serves as a check valve for apertures 45 provided in the pisto-n 4I. A compression spring 44a encircling the stationary contact 31 may be provided to form Ya resilient stop for the upward travel of the washer member 44.

The operation of the circuit interrupter shown in Fig. 5 will now be explained. When the movable contact 2 (not shown in Fig. 5) is withdrawn from the stationary contact 31, an arc will be drawn to create pressure within the arc interrupting chamber 5. This pressure will force the stationary Contact 31 downward and will close the washer member 38 over the apertures 40 provided in the guide web 38. The downward movement of the stationary contact 31 will also carry downward the piston 4I opening the check valve 44, thus permitting oil to flow through the apertures 45 in the piston 4I to the top side of the piston 4 I The compression spring 43 will be compressed until the pressure subsides within the arc interrupting chamber 5, at which time the compression spring 43 will move the piston 4I upward closing the check valve 44 to force oil upward through the apertures 40 raising the check valve 39 to consequently result in fresh oil of high dielectric strength completely covering the stationary contact 31 and washing products of decomposition upwards out of the chamber 5. It will be noted that the diameter of the piston casing 42 is sufficiently large so that the oil moved by the piston 4I is suioient in quantity to completely cover the stationary contact 31 when it is in its upper position.

It will furthermore be noticed that I have provided a circuit interrupting structure in which the stationary contact is responsive to the aro pressure produced in the chamber 5 to effect a very rapid lengthening of the arc which is drawn between the stationary Contact 31 and the movable contact 2 (not shown). Thus the length of the arc is not only determined by the movement of the contact operating mechanism moving the movable contact 2, but also by the pressure created in the interrupting chamber 5. Consequently, upon the interruption of high currents the arc will be rapidly lengthened by the downward movement of the stationary contact 31 in addition to the operation of the normal movable contact operating mechanism. It is apparent that the motion of the stationary contact 31 in response to the arcing pressure created within the interrupting chamber 5 facilitates the interruption of the arc by the rapid lengthening thereof.

.It will furthermore be noticed that fresh arc extinguishing liquid is drawn into the piston casing 42 during each circuit opening operation, thus providing a circulation of oil completely through the arc interrupting chamber 5.

The interrupter shown in Fig. 6 is similar to the interrupter just described in connection with Fig. 5 except that a resilient washer member 46, composed of a resilient material, such as leather, may be used to simplify the valve structure attached to the lower end of the stationary contact 31. The resilient washer member 46 is rigidly secured to the lower end of the stationary co-ntact 31 by means of two washers 41, 48 fastened to the lower end of the stationary contact 31 by nuts 49, 50. rIhe operation of the flushing system shown in Fig. 6 is the same as .that previously described in connection with Fig. 5, namely, the arcing pressure forcing the stationary contact 31 downward to force oil above the resilient washer member 45 and to compress the compression spring 43. Upon the subsidence of pressure Within the arc interrupting chamber 5, the compression spring 43 will retract the stationary contact 31 forcing oil up through the apertures 40 in the guide web 38 and through the check valve 39 to flush out the arcing chamber 5. Again the diameter of the piston casing 42 is such as to move a suicient quantity of oil to cover the stationary contact 31 when the latter is in its normal raised position.

It will be noted that the circuit interrupters in Fig. 5 and Fig. 6 provide a resilient mounting for the stationary contact 31 by the provision of the compression spring 43. Consequently, part of the movement of the stationary contact 31 may be used, when desired, to take up the shock of the movable contact 2 striking against the stationary contact 31 during a closing operation of the interrupter.

It will be apparent that my invention is not only applicable t0 a liquid type circuit interrupter, but it may also be applied to a circuit interrupter operating in a gaseous medium, such as air. The energizing of the ushing system is merely dependent upon the arcing pressure and it is not necessary to have a liquid medium in which the arcing pressure is formed. The arc extinguishing medium and also the flushing medium may be a gas, such as air, in any of .the circuit; interrupters previously described. Merely for purposes of illustration only, and not by way of limitation, have I described my invention in connection with a liquid type circuit interrupter.

It will furthermore be observed ythat not only have I utilized the aroing pressure to energize a flushing system operative upon a subsidence of the arcing pressure, but also I have utilized the arcing pressure to produce a rapid motion of the stationary contact, which rapid motion of the stationary contact is effective to lengthen rapidly the arc and to facilitate its interruption. This feature of my invention, namely, the movement of the stationary contact in response to arcing pressure to elect a rapid lengthening of the arc, is independent of the ilushing system and may be used on any interruptor which need not have any formof flushing system.

Although I have shown and described particular structures, it is to be understood that the same were for illustrative purposes and that changes and modications may be made by those skilled in the art without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. In a circuit breaker, means defining an arcing chamber, means for establishing an arc within said arcing chamber, a second adjacently disposed chamber, a compressible fluid partly filling said second chamber, a first valve means connecting said two chambers to compress said compressible iiuid during the establishment of said arc, a, second valve means operative after the subsidence of pressure Within said arcing chamber to utilize the energy stored in said compressible iluid for flushing out said arcing chamber.

2. In a liquid break circuit interrupter, an arcing chamber immersed in an arc extinguishing liquid, means for establishing an arc within said arcing chamber, an adjacently disposed fiushing container only partly filled with said arc extinguishing liquid, a first valve means connecting said arcing chamber with said flushing container for utilizing the arcing pressure to compress the iiuid above the liquid within said flushing container, a second valve means operative after the subsidence of arcing pressure for permitting the compressed fluid within said flushing container to force liquid within said flushing container into said arcing chamber to flush the latter.

3. In a circuit interrupter, an arcing chamber, means for establishing an arc Within said arcing chamber, an adjacently disposed iiushing container, a movable piston within said ilushing container, valve means connecting said arcing chamber with said iiushing container on one side of said piston, a compressible fluid within said flushing container on the same side of said piston, said valve means permitting a compressing f said compressible fluid during the arcing period, a second valve means connecting the other side of said piston with said arcing chamber, said second valve means being operative after a subsidence of arcing pressure to permit said compressed fluid to force said piston to move, said piston forcing arc extinguishing fluid through said second valve means .to flush said arcing chamber after a circuit opening operation,

4. In a circuit interrupter of the liquid break type, an arcing chamber immersed in an arc extinguishing liquid, means for establishing an arc within said arcing chamber, an adjacently disposed flushing container only partly lled with arc extinguishing liquid, the rest of said flushing container being lled with a compressible huid, apiston disposed Within said iiushing container, valve means between said arcing chamber and said flushing container to permit the pressure of arcing to compress said compressible huid within said flushing container, a second valve means connecting said arcing chamber with said flushing container to permit liquid contained within' said flushing container to be forcedby said compressed fluid within said flushing container through said second valve means to flush out said arcing chamber upon the subsidence of arcing pressure herein.

5. In a circuit interrupter, an arcing chamber, means for establishing an arc Within said chamber, an adjacentiy disposed flushing container, valve means disposed between said arcing chamber and said iiushing container, a compressible fluid within said iiushing container, a volumemuitiplying piston disposed Within said flushing container, and second valve means connecting said flushing container with said arcing chamber, the arrangement being such that arcing pressure compresses said compress'ible fluid within said flushing container and when the arcing pressure subsides .the compressible fluid forces the piston to .move the force arc extinguishing fluid through said second-mentioned valve means to flush said arcing chamber.

6. In a circuit interruptor of the liquid break type, an arcing chamber immersed in arc extinguishing liquid, means for establishing an arc within said arcing chamber, an adjacently disposed iiushing container being only partly filled with arc extinguishing liquid, the rest of said fiushing container being lled with a compressible fluid, a first valve means connecting the arcing chamber With the iiushing container, a volume-multiplying piston disposed Within said flushing container, a second valve means connecting said arcing'chamber with said iiushing container, the arc pressure within said arcing chamber acting through said mst-mentioned valve means to compress said compressible fluid within said flushing container, said second-mentioned valve means being operative to permit said piston to force arc extinguishing liquid into said arcing chamber following the subsidence of pressure Within said arcing chamber.

'7. In a liquid break circuit interrupter, an arcing chamber immersed in an arc extinguishing liquid, means for establishing an arc Within said arcing chamber, an adjacently disposed flushing container only partly filled with arc extinguishing liquid, the rest of said flushing container being `lled with a compressible iiuid, valve means connecting said arcing chamber with said ilushing container, a volume-multiplying piston disposed within said flushing container having the small area working surface toward said compressible fluid, spring means biasing said piston toward said compressible huid, valve means carried by said piston to facilitate the refilling of said flushing container, and a third valve means connecting said arcing chamber with said flushing container, the arrangement being such that the 40farcing pressure compresses said compressible fluid through said first mentioned valve means, the third mentioned valve means permitting the piston t0 force liquid into said arcing chamber upon the subsidence of arcing pressure therein.

'8. In a circuit interrupter, an arcing chamber, means for establishing an arc within said arcing chamber, an adjacently disposed flushing chamber, a piston disposed within said flushing chamber and extending into said arcing chamber, a valve carried Iby said piston, a iiuid connection through said piston, the arcing pressure forcing said piston into said ilushing chamber, spring means for biasing said piston into said arcing chamber, second Valve means carried by said piston within said flushing chamber, the return of said piston by said spring means following thei subsidence of arcing pressure forcing arc extinguishing fluid through said fluid connection in said piston into said arcing chamber to flush the latter following the circuit opening operation.

9 In a liquid ,break circuit interrupter, .an arcing chamber immersed in an arc extinguishing liquid, mea-ns for establishing an arc within said arcing chamber, a piston extending through the wall of said chamber and responsive to the pressure therein, a fiuid connection through said piston, means biasing said piston into said arcing chamber, an adjacently disposed piston casing, said piston being movable in the adjacently disposed piston casing, valve means carried by the part of said piston movable Within said piston casing to charge said piston with arc extinguishing liquid following the movement of said piston into said piston casing, the arrangement being such that the arcing pressure forces said piston into said piston casing to charge it with arc extinguishing liquid, the piston being movable back into said arcing chamber upon the subsidence of arcing pressure to force liquid through said fluid connection to flush out said arcing chamber following a circuit opening operation.

10. In a circuit interrupter, an arcing chamber, an adjacent disposed piston casing, a first contact disposed within said arcing chamber, a movable contact cooperating with the rst contact to establish an arc within said arcing chamber, said first contact .being movable into the adjacently disposed piston casing upon the establishment of an arc, valve means carried by the end of said first contact movable in said piston casing, said valve means being operable to force arc extinguishing fluid into said arcing chamber following the subsidence of arcing pressure upon the retraction of said first contact into said arcing chamber.

11. In a liquid break circuit interrupter, an arcing chamber immersed in an arc extinguishing liquid, a iirst contact and a movable Contact cooperable therewith to establish an arc within said arcing chamber, an adjacently disposed piston casing, said rst contact being movable into said piston casing upon the creation of arc pressure Within said arcing chamber, a check valve attached to the end of said first contact movable into said piston casing, a second check valve surrounding said lfirst contact, the arrangement being such that the arc pressure forces said first contact into said piston casing to charge the iirst contact with arc extinguishing liquid, the rst contact being movable back into said arcing chamber upon the subsidence of arcing pressure to force liquid through said second-mentioned check valve into said arcing chamber for flushing purposes.

12. In a circuit interrupter, an arcing chamber,

a first contact cooperable with a movable con;

tact for establishing an arc Within said arcing chamber, an adjacently disposed piston casing, said first contact being movable into said piston casing a flexible washer attached to the end of said first contact movable in said piston casing, the first contact being biased to its normal position Within said arcing chamber, the. arrangement operating to move said first contact into said piston casing during the establishment of an arc to charge said first contact with arc extinguishing fluid, the first contact being retractible into said arcing chamber following the subsidence of arcing pressure therein to force fluid into said arcing chamber for flushing purposes.

13. In a circuit interrupter of the liquid-break type, an arcing chamber, means for establishing an arc within the arcing chamber, an adjacently disposed chamber having an inlet into one part thereof and a separate outlet leading from another part thereof into the arcing chamber, and energy storing means charged by arcing pressure and operable upon decrease in pressure in the arcing chamber to force liquid from the adjacent ly disposed chamber through the outlet opening and into the arcing chamber.

14. In a circuit interrupter of the liquid-break type, an arcing chamber, means for establishing an arc within the arcing chamber, an adjacently disposed chamber having an inlet into one part thereof and a separate outlet opening leading from another part thereof into the arcing chamber, energy storing means charged by arcing pressure for forcing liquid from the adjacently disposed chamber through the outlet opening and into the arcing chamber, and a pressure responsive valve at the outlet opening responsive to the pressure in the arcing chamber for preventing the forcing of the liquid through the outlet opening and into the arcing chamber until after the pressure has subsided in the arcing chamber.

15. In a circuit interrupter of the liquid-break type, an arcing chamber, means for establishing an arc Within the arcing chamber, an adjacently disposed chamber having a piston therein, an outlet leading from the space at one side of said piston into the arcing chamber, means permitting flow of liquid within the adjacently disposed chamber from one side of said piston to the other side only in the direction which admits liquid into said space from which the outlet leads into the arcing chamber, and spring means charged by arcing pressure and biasing the piston to force liquid through the outlet and into the arcing chamber.

16. In a circuit interrupter of the liquid-break type, an arcing chamber, means for establishing an arc Within the arcing chamber, an adjacently disposed chamber having a piston therein, an outlet leading from the space at one side of said piston into the arcing chamber, means permitting flow of liquid within the adjacently disposed chamber from one side of said piston to the other side only in the direction which admits liquid into said space from which the outlet leads into the arcing chamber, spring means charged by arcing pressure and biasing the piston to force liquid through the outlet and into the arcing chamber, and one-Way valve means preventing W of liquid from the arcing chamber into the adj acently disposed chamber.

CLINTON L. DENAULT. 

